Curcumin-mediated photodynamic inactivation coupled with Cu2+-catalyzed Fenton-like reaction: a cascaded antifungal strategy against Fusarium graminearum and its applications.

A novel curcumin-mediated PDI coupled with Cu2+-catalyzed Fenton-like reaction was developed to explore its antifungal ability and mechanisms against Fusarium graminearum by analyzing ROS generation, cell membrane integrity, mitochondrial membrane potential (ΔΨm), spore germination and mycotoxin production. Results showed that this PDI could completely inactivate F. graminearum with 50 μM curcumin, 10.8 J/cm2 irradiation and 250 μg/mL CuCl₂. The potent mechanisms were attributed to the cytotoxic actions of Cu+ and •OH from Fenton-like reactions and cascaded redox reactions between Cu2+ and ROS generated by the PDI, which collectively damaged the cell membrane, degraded intracellular DNA and total proteins, disrupted ΔΨm and energy metabolism. Furthermore, this PDI significantly inhibited the spore germination of F. graminearum, suppressed the production of DON, reducing its contents to below the detection limit in maize and 0.17 μg/g in wheat. This study provides an efficient method to control fungal contaminations and their mycotoxins in food.